the 250hp dozer, fitted with a five-tyne, 12-foot-wide ripper, using the GPS data already gathered. "Myxomatosis and RHD have both given us huge production and biodiversity gains," David says. "However, science tells us that they, on their own, are not enough: the scientific evidence of damage at low rabbit densities is irrefutable." Dr Brian Cooke, program manager for the jointly funded AWI and MLA rabbit-control research program, has ascertained that "with up to two rabbits per hectare there is a reasonable chance of regeneration, at about three rabbits per hectare the chance of regeneration falls off quickly and at about four rabbits per hectare you can kiss goodbye to regeneration of even common shrub and tree species such as Callitris or Casuarina". Other members of the local Landcare group have also undertaken ripping of warrens and it is now thought that at least 100,000 of the estimated 176,000 in the area have gone. "Given the very low human population of much of Australia, and the limitations of boundary-to-boundary ripping in some regions, the need for another biological agent would seem to be the answer," David says. "It is irresponsible for Australians to expect producers to bear the full burden of rabbit control. We don't have the resources and we aren't the only ones outside of the metropolitan area using the land. "Environmental groups need to inform themselves in regard to rabbits and support us because there are huge gains in biodiversity to be had. If the status quo remains, the integrity of the biodiversity of arid and semi-arid Australia will continue to remain at risk, or the alternative is that rabbits can be suppressed further to a point where we can improve biodiversity. "There are whole suites of trees at risk because they have reached the end of their life and rabbits have prevented the recruitment of new generations. Furthermore, the productivity and longer-term viability of grazing systems based on native pastures will be best when biodiversity is healthy." ú More information: David Lord, 08 8091 1638, thackaringa@bigpond.com; Dr Brian Cooke, 02 6201 2032, brian.cooke@canberra.edu.au 13 INVASIVE ANIMALS BEYOND THE BALE New growth on a tiny saltbush that would once have been rabbit food on 'Thackaringa'. 50 50 Yield & Micron Staple Length & Strength Colour Dark & Medullated Fibre Fleece Measurement WOOL TESTS AVAILABLE FOR: AUSTRALIAN WOOL TESTING AUTHORITY LTD ABN 43 006 014 106 PO Box 240, North Melbourne Vic 3051 Email: awtainfo@awta.com.au Web: www.awta.com.au 70 Robertson Street, Kensington Vic 3031 Tel: 03 9371 4100 Fax: 03 9371 4191 Anti-rabbit research AWI and Meat and Livestock Australia (MLA) have joined forces to fund a number of projects to assess the threat posed by rabbits to Australian livestock producers. By examining the current status of rabbit haemorrhagic disease (RHD) and rabbit populations, the aim is to place the wool and meat industries in the "best possible strategic position" to minimise the present and future impact of rabbits. The Invasive Animals Cooperative Research Centre will manage the program. The former CSIRO researcher responsible for managing RHD's introduction into Australia, Dr Brian Cooke, has been contracted as project manager. David Lord is chairman of the advisory body representing the industries, which will liaise with Dr Cooke and the research programs. A pile of rabbits caught in 1939 on 'Thackaringa', Broken Hill. PHOTO: COURTESY DAVID LORD